This invention, in one of its aspects, relates to optical devices which project images and guide lines on a work surface. In a more specific aspect this invention pertains to units projecting guide lines or grid lines for use in accurately aligning figures, letters, symbols and other images during lay out operations. In the course of graphic design operations, such tasks as image layout, the aligning with their backgrounds of letters or words for posters and signs, architectural design, mosaic tile design, type setting, and similar lay up work require guidelines for proper alignment. The provision of guide lines is best accomplished optically.
An optical paste-up aligning device is described in U.S. Pat. No. 3,323,415. The aligning device will transmit guide line images and superimpose them on the surface of a paste-up paper or base sheet so that an operator can easily produce paste-up copy with all of the individual pieces in their proper relationships. When the screen is positioned between a grid plate and the paste-up sheet, a virtual image of the grid is obtained which appears to be superimposed in the plane of the paste up. This image can then be used as a guide for pasting down the pieces during the paste-up operation. As pointed out in that patent, previously, in order to obtain the proper alignment of copy it was necessary to use a T-square, triangles and rulers.
Another projector of the same type is the subject of U.S. Pat. No. 3,749,485. The principles of shadow-line projectors are used in establishing reference lines to assist workmen in assembling a number of components in particular dimensional relationships with each other. Known forms of shadow-line devices are not practical for this sort of assembly operation. The projector disclosed in U.S. Pat. No. 3,749,485 establishes a series of stripes on a transparent sheet. The stripes are opaque and of such a width that they project a particular width of shadow on the work surface. The reference shadow-lines are generated by intercepting light from a light source with the interference lines established by the stripes.
A still different type of projector is the subject of U.S. Pat. No. 4,910,541. In this patent the difficulties of using a T-square and triangle are also alluded to. The handling of these implements is awkward and time consuming. In addition one's hands are not free to work with the laying of small pieces. A light line projecting device is described wherein measured bars of light are simply adjusted over the layout sheet. A horizontal bar of light is moved by merely adjusting a turn knob which can move the light bar down the work sheet, starting from the top. Measuring rulers are provided, one across the top of the work sheet supporting platform, and the other ruler along one side edge of the work sheet. The light bars provide the straight edge guides by which paste up or lay out operations can be carried out.
The prior art can be further exemplified by U.S. Pat. No. 4,696,400 directed to a kit for creating wall murals. The kit includes a slide transparent panel and a projector for projecting the image on the transparent panel onto a selected wall.
The prior art patents solve the problem of improving paste up, lay out, and drawing operations by eliminating penciled in guide lines through the projection of reference lines. But a review of that art reveals that they are subject to improvement. One drawback is that there is no provision for moving, repositioning, or partially rotating, the images and reference lines relative to the work piece during the design layout operation. In addition they include no provision for changing an image size in, say, one portion of the work when such changes are required during the progress of the work. In U.S. Pat. No. 3,323,415, for instance, the light source and grid plate are installed in a housing, fixing the distance from the paste-up sheet. In U.S. Pat. No. 3,749,485 the projector is mounted on a framework as shown in FIG. 1 of that patent. This also allows for only one preset distance between the projector and the work surface. In U.S. Pat. No. 4,910,541 a framework also fixes the distance of the light projecting fixture from the work area. Likewise the wall mural kit is secured to an opposite wall by nails, pins or screws. This also fixes the distance of the device from the work surface.
More important, it is frequently necessary to turn or angle the reference lines from their starting positions during the lay up operation to achieve an angular effect. The prior art devices do not allow such latitude, and hence are often ineffective. A case might possibly be made for the combination of U.S. Pat. No. 2,717,530 with U.S. Pat. No. 5,103,384. However U.S. Pat. No. 2,717,530 is concerned with a hand-held optical pointer, and U.S. Pat. No. 5,103,384 discloses a flashlight holder for mechanics requiring light while working on automobiles. To replace the flashlight in a flashlight holder with a pointer designed to be hand-held is contrary to the hand-held pointer invention. It is stated in U.S. Pat. No. 2,717,530 that various pointing positions are shown in FIG. 1. It is obvious that they can be achieved by turning or twisting the hand which is holding the pointer. A diaphragm plate can be rotated by the finger or thumb. Obviously this would be supplemental, such as for minor adjustments or fine tuning.
Herein, then, not only are partial rotation of guide lines provided for, but size changing disadvantages of the prior art apparatus are overcome. As will be apparent a device is provided which utilizes different projecting precepts. Means are provided for ensuring that parallel guide lines are projected.